Examples Of Configuration For Multipump Systems; Et: Max. Switching Time - DAB e.sybox Instructions Pour L'installation Et L'entretien

The state of configuration as a reserve can be seen as follows: on the Mul-
ti-pump System page, the top of the icon is coloured; on the AD and main
pages, the communication icon representing the address of the device
appears with the number on a coloured background. There may be more
than one device configured as reserve in a pumping system.
Even though the devices configured as reserve do not participate in nor-
mal pumping, they are nevertheless kept efficient by the anti-stagnation
algorithm. The anti-stagnation algorithm changes the starting priority once
every 23 hours and allows the accumulation of at least one continuous
minute of supply of flow from each device. The aim of this algorithm is
to avoid the deterioration of the water inside the impeller and to keep the
moving parts efficient; it is useful for all devices and especially for those
configured as reserve, which do not work in normal conditions.

7.6.10.1 - Examples of configuration for multipump systems

Example 1:
A pump set composed of 2 devices (N=2 detected automatically) of which
1 set active (NA=1), one simultaneous (NC=1 or NC=NA since NA=1) and
one as reserve (IC=reserve on one of the two devices).
The result obtained is the following: the device not configured as a reserve
will start and work by itself (even though it does not manage to bear the
hydraulic load and the pressure achieved is too low). If it has a fault, the
reserve device steps in.
Example 2:
A pump set composed of 2 devices (N=2 detected automatically) in which
all the devices are active and simultaneous (factory settings NA=N and
NC=NA) and one as reserve (IC=reserve on one of the two devices).
The result obtained is the following: the device that is not configured as
reserve always starts first, if the pressure detected is too low the second
device, configured as reserve, also starts. In this way we always try to pre-
serve the use of one device in particular (the one configured as reserve),
but this may be useful in case of necessity when a greater hydraulic load
occurs.
Example 3:
A pump set composed of 4 devices (N=4 detected automatically) of which
3 set active (NA=3), 2 simultaneous (NC=2) and 1 as reserve (IC=reserve
on two devices),
The result obtained is the following: at the most 2 devices will start at the
same time. The operation of the 2 that can work simultaneously will take
place in rotation among 3 devices so as to respect the maximum exchange
time of each (ET). If one of the active devices develops a fault no reserve
starts up because more than 2 devices cannot start at one time (NC=2)
and there are still 2 active devices present. The reserve intervenes as soon
as another of the 2 develops a fault.

7.6.11 - ET: Max. switching time

Sets the maximum continuous working time of a device in a set. It is signif-
icant only on pump sets with interconnected devices. The time can be set
between 1 min and 9 hours; the factory setting is 2 hours.
When the ET of a device has elapsed the system starting order is reas-
signed so as to give minimum priority to the device on which the time has
elapsed. The aim of this strategy is to use less the device that has already
worked and to balance the working time between the various machines
that make up the set. If the hydraulic load still requires the intervention of
the device, even though it has been put last in starting order, it will start to
guarantee pressure boosting of the system.
The starting priority is reassigned in two conditions based on the ET time:
1. Exchange during pumping: when the pump remains on without
interruption until the absolute maximum pumping time has been
exceeded.
2. Exchange to standby: when the pump is on standby but 50% of
the ET time has been exceeded.
If ET has been set at 0 there will be exchange to standby. Whenever a
pump in the set stops, a different pump will start first next time it is restart-
ed.
If the parameter ET (Max. switching time) is set at 0, there will
be exchange at each restart, irrespective of the pump's actual
work time.
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